That’s not entirely un-reasonable. Hopefully the Navy can get some migration support in that sum a well.
When I worked, I was employed by a large bank that employed 260,000 people.
Our migration from Windows XP to Windows 7 took three years, and involved tens of thousands of custom applications and vendor products. It was very painful for everyone, and cost hundreds of millions of dollars.
They need to migrate to Linux. Hell the NSA has their own version they can use. For all the money they’re spending, they could hire their own coders.
I tried to tell some that XP Pro was the one operating system that DOD contractors felt was the most secure.